Closures

Closures

A closure is a function that captures variables from its enclosing scope. In Lua, functions are first-class values and naturally form closures:

function makeCounter()
  local count = 0
  return function()
    count = count + 1
    return count
  end
end

local counter = makeCounter()
print(counter())  -- 1
print(counter())  -- 2
print(counter())  -- 3

Each call to makeCounter() creates a new, independent counter.

Anonymous Functions

Functions can be stored in variables:

local double = function(x)
  return x * 2
end
print(double(5))  -- 10

Your Task

Write a function makeAdder that takes a number n and returns a function that adds n to its argument.